1. Field of the Invention
The present invention relates to a polyphase stator having insulating members interposed between the coil ends of polyphase windings disposed in slots in a stator core, and a method of producing such a polyphase stator.
2. Description of the Related Art
Generally, electric motors comprise a stator core having as many windings as the number of phases and a rotor having a plurality of permanent magnets on its outer circumferential surface and positioned rotatably in the stator core. The stator core is composed of a stack of steel sheets joined integrally together, and has a plurality of slots defined in its inner circumferential surface. The windings are disposed in the slots of the stator core.
The windings comprise insulated conductive wires, e.g., coils of enameled wire, and are inserted in the slots with sheets of insulating paper (insulating members) disposed between the coil ends of the windings to electrically insulate the windings. Each of the sheets of insulating paper is usually of a planar shape rolled and brought into position each time one phase of winding is inserted into the stator core.
Since the sheets of insulating paper are planar, however, they cannot be held between the windings if the gaps between the windings are increased. Therefore, the sheets of insulating paper tend to be removed from between the windings or displaced out of position, failing to keep the windings effectively insulated.